Safety device for hydraulic brakes



Aug. 30, 1938. R. N. ROEN 2,128,853

SAFETY DEVICE FOR HYDRAULIC BRAKES Filed May 10, 1938 ATTORN EYS Patented Aug. 30, 1938 UNITED STATES PATENT orr cr.

SAFETY DEVICE zo i t fr snawuo BRAKES z I I v 113222.2'35tf23222f2fi12. 2:22;: 2 Claims. (01. 303-84) My invention relates to improvements in hydralic braking devices and more particularly to the liquid control devices used in connection with four wheel hydraulic brakes of motor vehicles.

In the conventional type of hydraulic braking devices, such as used in connection with four wheel hydraulic brakes for motor vehicles, the liquid employed in such devices or systems is controlled from a single cylinder by a single plunger operated by the brake pedal of the motor vehicle and a single conduit leading from the cylinder to all of the wheel braking units. In a construction of this character should the conduit develop a leak or be ruptured, the entire braking system is rendered inoperative. Should this occur during the operation of the motor vehicle and whether the same be noted or not by the operator, it would preclude the operator from having a braking control over the motor vehicle and thus constitute a serious menace to the passengers of the vehicle as well as to the public.

Therefore, it is one of the principal objects of my invention to provide a device equipped with means operable upon leakage or line rupture to 25 maintain a pair of the brake operating units in operating condition while the other pair of brake operating units are inoperative, thereby permitting the operator to exercise sufficient braking control over the motorvehlcle until such time as 30 the motor vehicle may be brought to a stand-still and the damage to the parts repaired.-

Another object of my invention is to provide a device of the above described character which is simple in construction, durable in use, highly efa motor vehicle equipped with four wheel type of brakes.

Figure 2 is a horizontal sectional view of my device.

Figure 3 is a central transverse sectional view 55 of my invention.

flcient in operation and economical in manufac-.

Figured is an enlarged detail sectional view illustrating the construction of one ,of theauxiliary ports.

In practicing my invention thereis illustrated a master brake cylinder 5 of a motor vehicle of 5 ordinary construction, the same being employed in connection with a brake pedal to eifect actuation of brake unitsG. The brake units 6 are connected together in pairs forming front and rear pairs on the front and rear wheels respec- 10 tively by means of lines I and 1a. My device comprises a cylinder l0 having open ends closed by caps Ii. Said caps have pipe connections I2 and i3 respectively. The pipe connection i2 is connected to the front line I by means of a pipe 15 I4 while the pipe connection I3 is connected to the rear line Ia by means of a similar pipe l5.

Intermediate the ends thereof the cylinder is fashioned with a pipe connection l6 connected to the master cylinder 5 by means of a pipe l1. 0 Slidable within the cylinder I0 is a pair of opposed cup shaped pistons l8 having seated therein the ends of coil springs IS, the opposite ends of said coil springs being seated within the. caps II and said springs normally urge the pistons towards each other. c

Journaled in a bearing formed on the i'r' ner wall of the cylinder I0 is a shaft 20 having*-fix'ed on the inner end thereof an elongated cam member 2| for engagement with the inner faces of the pistons whereby to maintain the same in spaced relation against the action of the springs l9.

Said shaft extends without the cylinder and is provided with adjusting nuts 22 whereby said cam may be readily adjustable to a desired position within said cylinder for a purpose hereinafter described. The outer wall of the cylinder is fashioned with a by-pass chamber 23 communicating with the interior of the cylinder and centrally thereof by means of a port 24 located diametrically opposite the bore of the pipe connection i6. Spaced on each side of the port 24 is a smaller port 25 effecting communication between the by-pass chamber and the interior of the cylinder. Said ports 25 are normally closed by the pistons l8 when the cam 2| is adjusted to maintain the pistons in their extreme spaced positions relative to each other as illustratedin Figure 2.

Adjacent the ports 25 the cylinder is fashioned with auxiliary ports 26 of a relatively small diameter whereby to maintain fluid in the lines I4 and I5 from the line H through the port 24 and chamber 23. The ports 28 are of a size while per- 56 mitting fluid to pass therethrough for the purpose of contraction and expansion due to the temperature changes, do not permit a sufficient quantity to pass therethrough to operate the brake units 6.

Each of the pistons ll adjacent the outer ends are fashioned with circumferentially extending grooves 21. Said grooves are adapted to receive therein spring pressed balls mounted within a housing 29 formed on the cylinder. 7

.Suitable screws 30 are employed to maintain said balls within said housing in operating condition. The inner faces of the caps I I are provided with gaskets II serving as fluid seals for the outer faces of the pistons it when the same are actuated thereagainst.

In operation, fluid having been introduced into the cylinder, by-pass chamber and connected lines I, I4 and I5, pressure is applied thereto within the master cylinder 5 thereby exerting pressure against the inner faces of the pistons l8 and causing the same to move towards the ends of the cylinder. This movement of the pistons serves to force the liquid in the pistons between the caps H and pistons l8 into the pipes II and I! for actuating the brake units 5 in the usual manner.

Upon the rupture or leakage of one of the lines connected to the cylinder l0, for instance by way of example line ii, the fluid in said line I5 will be discharged therefrom permitting the respective pistons controlling the line to be moved into engagement with the gasket 3| of the cap II and effect seating of the ball 28 within the groove 21, thereby maintaining said piston in a locked position and preventing fluid from the cylinder from entering the line l5. When the piston is thus locked the opposite piston continues to function in the usual manner.

' Obviously, a leak or breakage in the line on the opposite side of the cylinder I!) would cause a reverse operation of the parts heretofore described and maintain the other parts in operating condition.

In instances where it is necessary to efl'ect a bleeding of the connected lines the shaft 20 is adjusted to position the cam to permit the pistons under the action of the springs II to move closer together and open the ports ll.

From the foregoing'will be apparent that my invention provides a simple and reliable means whereby the front or rear braking units are maintained in operating condition upon a rupture or leak in the line connecting the other braking units to the master cylinder and thereby permits the operator of a motorvehicle to maintain a braking control thereover.

What I claim is:

1. A device of the character described, comprising, a cylinder adapted to be fllled with a brake operating fluid, opposed pistons operable in said cylinder, "springs within said cylinder for urging said pistons towards each other, said cylinder formed with a by-pass chamber, a port effecting communication with the interior of said cylinder and said chamber between said pistons, a pair of ports eifecting communication between said chamber and said cylinder and normally closed by said pistons, auxiliary ports effecting communication between said chamber and said cylinder, a. cam mounted in said cylinder between said pistons for maintaining said pistons in spaced relation to effect a closing of said pair of ports, and means carried by said cylinder for latching said pistons against movement.

2. A device of the character described, comprising, a cylinder adapted to be fllled with a brake operating fluid, opposed pistons operable in said cylinder, springs within said cylinder for urging said pistons towards each other, said cylinder formed with a by-pass chamber, a port effecting communication with the interior of said cylinder and said chamber between said pistons, a pair of ports effecting communication between said chamber and said cylinder and normally closed by said pistons, auxiliary ports effecting communication between said chamber and said cylinder, and a cam mounted in said cylinder between said pistons for maintaining said pistons in spaced relation to eflect a closing of said pair of ports.

RAYMOND N. ROEN. 

